MDM Observatory 1.3m Telescope Observer's Report for 2002 Apr 27

Observer(s): Sugerman/Mroczkowski
Institution(s): Columbia

Instrument: Wilbur

Worked for 8 hours (all night)
Conditions were Mixed most of the night.
Problems were encountered, see the separate trouble report for details.

Seeing and Weather:
   Clouds from 4:30  until 6:00.
   Beg: Seeing 1.2 arcsec, Clear, Winds Calm
   Mid: Seeing 1.4 arcsec, Clear, Winds Calm
   End: Seeing 1.2 arcsec, Cirrus, Winds Calm

Observing Summary:

light cloud cover at beginning and end of night.  Focus in V was very 
difficult to maintain, while focus in R was steady (we varied between
the two filters regularly).  Within 10-20 minutes of focusing in V
the PSF would spread out horzontally, eventually becomming a double image
with a coma smear downward.  However, R did not show this at all.  Also,
the  best focus  in V varied fairly dramatically over the night 
(e.g. it was about 5030 at the beginning, dropped to 5010 then up to
5045 over the night).  If a similar thing happened in R, I'd blame
myself for bad focus, but as V degraded, R PSF's remained round and
had reasonable FWHM (3.9 pix).

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Submitted on 2002 Apr 28 [4:28:39]